Safety fuses have been used for many years for the ignition and detonation of various types of explosives. At the present time, there are two types of safety fuse which are presently in use. The safety fuse which is used by the military and government is a composite of black powder which has an external layer or wrap of textile material. An outer sheath or layer of relatively smooth plastic is provided to maintain and provide a water-proof condition so that the fuse can be used in all types of environment.
The type of safety fuse which is primarily used for commercial use is slightly different from the military type in that a layer or coating of asphalt is applied to the outside surface of the textile wrap provided on the fuse. This asphalt layer is used as a sealant between the fuse and the blasting cap or ignition device. In this way, the entire assembly is sealed to prevent water from entering the connection with the ignitor or blasting cap which, in turn, would render the fuse, ignitor or blasting cap unreliable or inoperative.
The military type safety fuse, because it has a relatively smooth outer plastic layer, does not inherently provide this sealing effect. As a result, it is necessary to provide a separate sealing arrangement to prevent the introduction of water in the connection between either the igniter or the blasting cap.
The prior art device which is used by the military and other government agencies to ignite military type safety fuse is the M-60 igniter which was intended to be a reusable igniter. After being used to ignite a fuse, the igniter is removed from the burnt fuse, disassembled and a new primer charge is inserted, thus, the unit is reloaded and is again ready to be used.
It is a common known fact, however, that most M-60 igniters are not reused. The operation requiring the ignition or lighting of a fuse leading to an explosive charge is a nervous and dangerous time for all participants. As a result, it is very unlikely (not to mention unsafe) that a serviceman or other user will take the necessary time to remove the M-60 igniter from the fuse either before or after the charge has exploded. Hence, in most cases the M-60 igniter is discarded and not reused. This is especially true because the serviceman, in most cases, has an endless supply of igniters which minimizes the necessity to reload the igniter. In addition, the cost to retrieve, reload the M-60 and stock spare primers must come close to or exceed the cost of the M-60.
As a result of the fact that the M-60 igniter is relatively expensive, it has been shown that there is a definite need for a disposable type fuse igniter which is not only inexpensive to produce so that it can be discarded, but also must be extremely reliable and meet all military, government and commercial specifications. As a result, the present invention is directed to an inexpensive, water-proof fuse igniter which is a one-use throw-a-way disposable igniter.